JPH0670575A - DC brushless motor controller - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a control device for a DC brushless motor, which has a downsized and simplified structure and can suppress power consumption. [Structure] Drive power from an AC power source 22 is transformed. Bowl 23
Is input to the inverter circuit 24 via the
The motor circuit 24 controls the rotation state of the motor 25. The current on the primary side of the transformer 23 is detected by the speed control circuit 34 via the primary current detection line 35. On the other hand, the motor 25
The motor current is detected by the speed control circuit 31 as a voltage via the resistor 30. The ON / OFF state of the switching element 29 is controlled based on the detected current signal from the primary current detection line 35 and the control signal via the photocoupler 33 of the speed control circuit 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a DC brushless motor which is used, for example, to open and close an automatic door.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the electrical construction of a conventional motor control device 1. Motor control device 1
Includes a transformer 3 that transforms the power supply from the AC power supply 2. The output of the transformer 3 is converted into a DC voltage via the inverter circuit 4, and this DC voltage is supplied to the DC motor 5 as a drive voltage. A battery 6 is connected to the output side of the transformer 3 and charged by the transformer 3. The battery 6 drives the DC motor 5 when the AC power supply 2 fails, and opens and closes the automatic door driven by the DC motor 5 slightly.

The transformer 3 is provided with a power transformer 7 for transforming the driving power from the AC power source 2 and supplying it to the inverter circuit 4. Further, the primary side current is detected and detected. A current transformer 8 that outputs a signal is provided. A switching element 9 such as a power transistor is connected in series to the primary coil of the transformer 3, and the output voltage from the transformer 3 is adjusted by controlling ON / OFF of the switching element 9.

The detection output of the current transformer 8 is connected to the secondary coil of the current transformer 8 in series, and the diodes 10 and 12 are connected in parallel in the forward direction.
And a resistor 11 connected in parallel with the diode 12 and converted into a voltage, which is output to the speed control circuit 13.
The speed control circuit 13 is connected to the inverter circuit 4 and is a deviation between the rotation speed signal from the resistor 16 for detecting the rotation speed of the DC motor 5 as a voltage level and the output from the current transformer 8. Is detected, and a control signal to the PWM circuit 14 is generated based on a separately input reference speed signal.

The speed control circuit 13 outputs a control signal for eliminating the deviation to a PWM (pulse width modulation) circuit 14. The PWM circuit 14 has a pulse transformer 15
A control signal is output to the switching element 9 of the transformer 3 to control ON / OFF of the switching element 9. By the switching operation of the switching element 9, the output level of the transformer 3 is changed and the rotation speed of the DC motor 5 is controlled.

[0006]

The control device 1 of the above-mentioned prior art relating to the DC motor 5 is provided with the current transformer 8 and the pulse transformer 15, so that the configuration of the control device 1 becomes large and the power consumption is low. There is a problem of increasing. In addition, there is a problem that the cost increases due to an increase in the size of the structure.

An object of the present invention is to solve the above-mentioned technical problems, to provide a controller for a DC brushless motor, which has a compact and simplified structure and which can suppress power consumption.

[0008]

According to the present invention, driving power from an AC power source is input to an inverter circuit via a transformer, and an output from the inverter circuit rotates a DC brushless motor. In a DC brushless motor control device for controlling a state, a primary current detecting means for detecting a current on the primary side of the transformer, a motor current detecting means for detecting a motor current, and the primary current detecting means. And an energization control means for controlling the energization state of the primary side of the transformer based on the outputs from the motor current detection means and the motor current detection means.

[0009]

The controller according to the present invention inputs the driving power from the AC power source to the inverter circuit through the transformer and controls the rotating state of the DC brushless motor by the output from the inverter circuit. To do. At this time, the primary side current of the transformer is detected by the primary current detecting means. On the other hand, the motor current of the DC brushless motor is detected by the motor current detecting means. The energization control means controls the energization state of the primary side of the transformer based on the outputs from the primary current detection means and the motor current detection means.

Therefore, the need for using a current transformer for detecting the current on the secondary side of the transformer, a pulse transformer for controlling the pulse width of the energization state of the primary side of the transformer, etc. is eliminated, and the structure is simplified and simplified. , And power consumption can be suppressed.

[0011]

1 is a block diagram showing the electrical construction of a motor controller 21 for a DC brushless motor according to an embodiment of the present invention. The motor control device 21 includes a transformer 23 that transforms the power supply from the AC power supply 22. Transformer 23
Is converted into a DC voltage via the inverter circuit 24, and this DC voltage is supplied to the DC motor 25 as a drive voltage. A battery 26 is connected to the output side of the transformer 23 and is charged by the transformer 23. The battery 26 is used for the DC motor 25 when the AC power source 22 is out of power.
To automatically open and close the automatic door driven by the DC motor 25.

The transformer 23 is provided with a primary line 27 and a secondary line 28 for transforming the driving power from the AC power source 22 and supplying it to the inverter circuit 24.
A switching element 29 such as a power transistor is connected in series to the primary line 27, and the switching element 2
By the on / off control described later in 9, the transformer 23
The output voltage from is adjusted.

The inverter circuit 24 is connected to a resistor 30 through which a current of driving power supplied to the DC motor 25 flows. From the resistor 30, a rotation speed signal corresponding to the rotation speed of the DC motor 25 has a voltage level and the speed control circuit 31
Is output to. The speed control circuit 31 is realized as an integrated circuit element and is a switching circuit on the secondary side with respect to the transformer 23. In the speed control circuit 31, a reference voltage corresponding to the reference rotation speed of the DC motor 25 is supplied to the reference voltage generation circuit 3
Input from 2. The reference voltage generating circuit 32 may be a microprocessor or the like that controls the entire operation of an automatic door or the like in which the DC motor 25 is used, and may have a voltage that changes momentarily.

The speed control circuit 31 compares the reference voltage from the reference voltage generating circuit 32 with the rotation speed signal from the resistor 30 and outputs a deviation signal for eliminating these deviations. The deviation signal is output to the photocoupler 33. The signal from the photocoupler 33 is output to the speed control circuit 34 on the primary side of the transformer 23. Speed control circuit 34
May use the same configuration as the speed control circuit 31. The current detection line 35 from the primary side line 27 of the transformer 23 is connected to the speed control circuit 34, and the current flowing through the primary side line 27 of the transformer 23 is detected and input to the speed control circuit 34.

A reference voltage corresponding to the reference rotation speed of the DC motor 25 is input to the speed control circuit 34 from a reference voltage generation circuit 36. The reference voltage generating circuit 36 is
It may be the microprocessor or the like. The speed control circuit 34 compares the reference voltage from the reference voltage generation circuit 36, the deviation signal from the photocoupler 33 and the current flowing through the transformer 23 primary line 27 from the current detection line 35 to determine the deviation, It detects and outputs a deviation signal that eliminates these deviations. The deviation signal is output to the switching element 29 as an ON / OFF control signal to control ON / OFF of the switching element 29. The switching operation of the switching element 29 changes the output level of the transformer 23 and controls the rotation speed of the DC motor 25.

FIG. 2 is a circuit diagram showing a configuration example of the control circuit 21. The power source power from the AC power source 22 is full-wave rectified and smoothed by a rectifying / smoothing circuit 38 via a noise filter 37. The output of the rectifying / smoothing circuit 38 is input to the transformer 23. The output of the inverter circuit 24 is the distribution circuit 3
At 9, the DC three-phase motor 25 is time-sequentially distributed and supplied. Further, the inverter circuit 24 and the speed control circuit 31 are provided with a clock signal and a forward / reverse rotation signal from a control device 40 such as a microprocessor for controlling the operation of an automatic door using a DC three-phase motor 25 as a whole. Various control signals such as a reverse rotation control signal are input. In addition,
The DC circuit 24 is provided in the DC circuit 3 phase motor 25,
A signal from the hall element 41 that detects a signal corresponding to the rotation speed is input.

Another transformer 44 is provided on the output side of the noise filter 37, and two rectifying / smoothing circuits 42 and 43 are connected to the secondary side of the transformer 44.
A drive voltage is supplied to each of the various drive circuit elements provided in FIG.

The operation of the control device 21 of the above-described embodiment will be described below with reference to FIGS. 1 and 2. When the load of the DC three-phase motor (hereinafter abbreviated as a motor) 25 is changed in a normal operation, the speed control circuit 31 detects the rotation speed signal from the resistor 30. These deviations are detected based on the rotation speed signal and the reference voltage. Further, a control signal for eliminating the deviation is generated, and the speed control circuit 34 on the primary side is generated via the photo coupler 33.
Is output to. In the speed control circuit 34, the on / off state of the switching element 29, for example, the on-duty of the switching element 29 is changed based on the control signal. As a result, the secondary drive power output from the transformer 23 changes, and the inverter circuit 24 causes the motor 25 to operate.
The voltage applied to the motor 25 is changed so that the rotation speed of the motor 25 is controlled to match the reference rotation speed corresponding to the reference voltage.

On the other hand, when an abnormality such as a sudden overload occurs during operation of the motor 25, a rapid increase in the primary side current of the transformer 23 corresponding to the overload causes a current detection line 35.
Is detected by the speed control circuit 34. The speed control circuit 34 performs control such as rapidly reducing the on-duty of the switching element 29 based on the detected current signal and the reference voltage from the reference voltage generation circuit 36, and the inverter circuit 24 and The motor 25 is protected.

In this way, the control device 21 of this embodiment is
Then, it is possible to realize the control of the rotation speed of the motor 25 and the protection at the time of overload. In order to realize such a control operation, the need for providing the current transformer 8 and the pulse transformer 15 in the above-described conventional technology is eliminated, the configuration of the control device 21 can be downsized, and power consumption can be suppressed. You can Further, the cost can be suppressed in that the structure can be downsized and the power consumption can be suppressed.

[0021]

As described above, according to the present invention, the driving power from the AC power source is input to the inverter circuit through the transformer, and the DC brushless motor is output by the output from the inverter circuit. Control the rotation state of. At this time, the primary side current of the transformer is detected by the primary current detecting means. On the other hand, the motor current of the DC brushless motor is detected by the motor current detecting means. The energization control means controls the energization state of the primary side of the transformer based on the outputs from the primary current detection means and the motor current detection means.

Therefore, the need for using a current transformer for detecting the current on the secondary side of the transformer, a pulse transformer for controlling the pulse width of the energized state of the primary side of the transformer, etc. is eliminated, and the structure is simplified and simplified. , And power consumption can be suppressed.

[Brief description of drawings]

FIG. 1 is a control device 21 of a motor 25 according to an embodiment of the present invention.
It is a block diagram of.

FIG. 2 is a circuit diagram showing a configuration example of a control device 21.

FIG. 3 is a block diagram of a control device 1 for a conventional motor 5.

[Explanation of symbols]

 21 Motor Control Device 22 AC Power Supply 23 Transformer 24 Inverter Circuit 25 DC Brushless Motor 29 Switching Element 31, 34 Speed Control Circuit 33 Photocoupler 35 Current Detection Line

Claims (1)

[Claims] 1. A DC brushless motor for inputting drive power from an AC power source to an inverter circuit via a transformer and controlling the rotating state of the DC brushless motor with the output from the inverter circuit. In the controller of the motor, primary current detection means for detecting the current on the primary side of the transformer, motor current detection means for detecting the motor current, the primary current detection means and motor current detection means DC brushless motor characterized by including an energization control means for controlling the energization state of the primary side of the transformer based on the output from the transformer.
Control device.